Pipettes are common tools used in medical diagnostic laboratories to transport measured volumes of bodily fluid samples, such as blood and urine. There are many different styles of pipettes that work by different mechanisms, most commonly piston driven pipettes and vacuum assisted pipettes. Generally, pipettes have a cylinder, graduated or not, that can be filled with a fluid using a pressure mechanism on one end of the cylinder. Disposable and single use pipettes are often made of polyethylene.
There is a need for improved pipettes that can do more than just transfer measured volumes of sample. Specialized syringes or pipettes that can also perform a function such as conduct a chemical analysis of some of the properties of the sample or dilute a sample are the subject of the present application.
Urinary dip strips are in common usage. Small improvements to ergonomics, handling ease and general efficiency can be very significant because so many of these manual tests are done. Samples are commonly collected from wide-mouth containers, such as cups. Fluid is then poured into a test tube (unless a very large volume of urine has been collected). A dip strip is then inserted in the test tube to contact all reactive paper pads, then it is removed and either held in the hand or placed on an absorbent paper while color develops.
Some analytical methods require high dilution factors. Assay of Hemoglobin A1c in blood is one example. The high dilution requirement can have several reasons but a typical reason is to reduce the interference that can result from high concentration of some components other than the target of the assay. Samples are commonly serially diluted, so that a small volume is diluted with a larger one; then a small portion of this solution is subsequently diluted with a larger portion of diluent. An example is the Siemens DCA Vantage® HbA1c assay, in which a small capillary is loaded with blood sample and then positioned in a cassette and during the assay process fluid is flooded into the corner of the cassette containing the pipette. There is a need for a more simple dilution process.